Polypropylene (PP) is a versatile thermoplastic resin available in a wide range of formulations from general purpose homopolymer, random copolymer, and impact copolymer grades to highly specialized resins for engineering applications. Grades of polypropylene are available to meet the needs of various fabrication processes such as extrusion, injection molding, thermoforming, blow molding, biaxially oriented film (BOPP), fiber spinning, slit tape, extrusion coating, and laminating. Polypropylene has good impact resistance and structural rigidity. It is unaffected by any solvent at room temperatures. It has excellent insulating properties and is extremely lightweight. Its high fatigue strength makes it a top choice under cyclic loading conditions. The wide range of physical properties and relative ease of processing make polypropylene an extremely attractive material capable of competing with more expensive resins in a number of demanding applications. For example polypropylene has very good resistance to fatigue, so that most plastic living hinges, such as those on flip-top bottles, are made from this material.
The ubiquitous use of PP in industry makes it a prime material candidate for a variety of applications where the PP comprises some or all of a surface. One of the drawbacks to using PP as surface is that materials that bind to PP are specific and lack flexibility as binding agents. So for example where a new coating for PP is desired, a new search for a PP binding molecule with the desired property must be conducted. The resulting search is costly in both time and resources and not guaranteed to be successful. A system that is flexible and can be easily tailored for a variety of materials to be bound to PP is needed. The use of peptides as linkers or binders to PP offers some potential in this regard.
Peptides having a binding affinity to polymer and plastic surfaces are known. For example, Adey et al., (Gene 156:27-31 (1995)) describe peptides that bind to polystyrene and polyvinyl chloride surfaces. Additionally, peptides that bind to polyurethane (Murray et al., U.S. Patent Application Publication No. 2002/0098524), polyethylene terephthalate (O'Brien et al., copending and commonly owned U.S. Patent Application Publication No. 2005/0054752), and polystyrene, polyurethane, polycarbonate, and nylon (Grinstaff et al., U.S. Patent Application Publication No. 2003/0185870) have been reported.
There remains a need therefore for a peptide based reagent that binds PP that offers flexibility in bring a wide variety of materials to the PP surface with minimum investment in redesign. Applicants have solved the stated problem by providing peptide reagents comprising PP binding peptides (PPBP). The PP binding peptides of the invention may be modified with other functional or binding peptides allowing for the delivery of benefit agents to the PP surface or for the use of the reagents to adhere PP containing surfaces.